Lecture 36: Evolution of the nervous system 2 Flashcards
Name 3 phylum?
porifera
cnidaria
mollusca
whats an example of a Porifera?
sponges
Do Porifera have neurones?
no
whats the sensory structure of the Porifera?
reactive ectoplasm
what an example a cnidaria and the neural organisation?
jellyfish and anemones
diffuse nerve net
whats an example of a Platyhelminthesand its neural organisation?
flatworm
Cerebral ganglia, longitudinal nerve cords, transverse connectors
which three phylum have a sensory structure known as ocelli?
Cnidaria
Platyhelminthes
Annelida
whats na example of a Mollusca?
Snails, slugs, squid
whats the neural organisation of a Mollusca?
Cephalic ring of several major ganglia and nerves
whats the sensory structure of a Mollusca involve?
Complex eyes, statocysts, chemo, olfactory and tactile receptors
what type of phylum are,
Insects, spiders, crustacea ?
Arthropoda
whats the neural organisation of Arthropoda
?
Cerebral ganglia, double ventral nerve cord and segmental ganglia
whats the sensory structure of anthropoda?
Compound eyes, mechano, chemo and olfactory receptors
Name 2 examples of Echnodermata
Starfish, sea urchins
hat neural organisation do Echnodermata have?
Nerve ring, radial nerves, subdermal plexus
sensory structures of Echnodermata
are?
Eyespots, epidermal sensory cells
what san example of chordata?
Vertebrates
whats the neural organisation of chordata?
Dorsal tubular brain and spinal cord, cranial, spinal and autonomic nerves
whats the sensory structures that Chordata have?
Special sense organs (hearing, vision, taste, smell, lateral line),
Spinal nerves are _______ like annelids
segmental
where is the nerve cord in a rat?
dorsal
where is a nerve cord in annelids and insects?
ventral
the beginning of the vertebrate nervous system started with?
Tunicate tadpoles
whats needed for a vertebrate nervous system?
Brain Dorsal nerve cord Notochord (developmental) Pharyingeal slits (developmental) Post-anal tail (developmental)
what stem difference between a ganglion and a Brain?
(1) a brain subserves the entire body, not just restricted segments;
(2) it has functionally specialized parts;
(3) it is bilobar;
(4) commissures and neurons form the surface with axons in the central core;
(5) interneurons are more numerous than primary motor or primary sensory neurons;
(6) multisynaptic rather than monosynaptic circuits predominate.
whats the NS of a roundworm like?
unsegmented nematode (ascaris) with dorsal and ventral nerve cords
whats the NS of a ribbon worm like?
nemertean with one dorsal and two ventral nerve cords and a cerebral ganglion
whats the NS of a leech like?
annelid (segmented) with cerebral ganglia and ventral nerve cord
whats the NS of a acorn worm like?
acorn worm (balanoglossus) a hemichordate with dorsal and ventral nerve cords
whats the NS of a amphioxus like?
a cephalochordate with dorsal nerve chord and notochord
where is the nerve cord located on a planarian?
lower centre section of the parenchyma
where is the nerve cord located on a nematode?
top and bottom centre
Tunicates have a _____ in the tadpole stage
notochord
whats the structure of a amphioxus?
Amphioxus has several chordate features Dorsal nerve cord Notochord Pharyngeal slits Myomeres Post-anal tail
Amphioxus nervous system has potentially _____ regions
homologous
what are some evolutionary trends?
- Increase in complexity
- New circuits added to old ones (layering)
- increase in size
- Absolute Vs relative
whats the jawless fish?
Myxine (hagfish)
